个人想法，提交是正确的

#include<stdio.h>

#include<math.h>

int main()

{

float a,b,c,p,q;

scanf("%f %f %f",&a,&b,&c);

float less(double a,double b,double c)

{

p=-b/(2*a);

q=sqrt(4*a*c-b*b)/(2*a);

printf("x1=%.3f+%.3fi x2=%.3f-%.3fi",p,q,p,q);

return 0;

}

float more(double a,double b,double c)

{

p=-b/(2*a);

q=sqrt(b*b-4*a*c)/(2*a);

printf("x1=%.3f+%.3f x2=%.3f-%.3f",p,q,p,q);

return 0;

}

float equal(double a,double b,double c)

{

p=-b/(2*a);

printf("x1=%.3f x2=%.3f",p,p);

return 0;

}

if((b*b-4*a*c)>0)

{

more(a,b,c);

}

else if((b*b-4*a*c)==0)

{

equal(a,b,c);

}

else

{

less(a,b,c);

}

 }